Soft scrollback for the Linux VGA console

If you're a heavy user of the Linux VGA console, you'll like this feature. Recent 2.6 kernels have added support for soft scrollback. This feature enables you to have much bigger scrollback buffer than the standard console has, at the price of slightly slower console output.

The scrollback buffer of the standard VGA console is located in VGA RAM. This RAM is fixed in size and is very small. To make the scrollback buffer larger, it must be placed instead in System RAM. We call this soft scrollback.

The feature and the size of the buffer are enabled/configured through kernel config options, during kernel compilation. Beside consuming kernel memory, enabling this feature will slow down the console by approximately 20%.

If you want this feature, say "Y" to VGACON_SOFT_SCROLLBACK kernel config item, and then enter the amount of System RAM to allocate for the scrollback buffer (VGACON_SOFT_SCROLLBACK_SIZE). Each 64KB will give you approximately 16 80x25 screenfuls of scrollback buffer.